The present invention relates to surgical instruments, and more particularly to corneal trephine instruments used in the removal and grafting of corneal "buttons."
Corneal transplants may be required for a variety of medical reasons. For instance, through accident, disease or old age, an individual's cornea may become occluded or otherwise impaired. Light rays are then substantially prevented from reaching the lens thus causing blindness or varying degrees of blindness. A method for alleviating blindness caused by defective corneas is the corneal transplant.
In a transplanting operation, the first step is to remove a corneal button from a deceased donor. An occluded or otherwise defective corneal button is then removed from a recipient and the corneal button from the donor is transplanted and sutured into position for grafting.
Various types of instruments are used presently by surgeons in removing corneal buttons. Prior art trephine instruments generally comprise a cylindrical cutting member having an annular blade. A surgeon must manually rotate the cutting member about its longitudinal axis in order to effect cutting action. It can be readily appreciated that considerable skill and dexterity is required in order for the surgeon to make a precise and uniform incision through the thickness of a cornea.
Prior art trephine instruments may require the surgeon to use a small table or bench on which to steady his hands. Even with the use of such a table, it is still extremely difficult for even a skilled surgeon to impart cutting action and maintain alignment during cutting of the cornea.
Accordingly, it is a general object of the present invention to provide a trephine instrument having a power-driven cutting blade mounted on an elongate handle which may be firmly gripped with both hands of a surgeon. The elongate handle includes first and second handle portions having their longitudinal axes offset from each other. A connecting handle portion provides a diagonal or offset which may extend over the nose bridge of the individual being operated upon.
Another object of the present invention is to provide a trephine instrument in which the power-driven cutting blade may be accurately and precisely extended and retracted relative to the handle. To this end, a simplified digital-operated shifting mechanism is appropriately provided.
Still another object of the present invention is to provide a trephine instrument in which the cutting blade is mounted on a guide formed of clear material, such as plastic, so the surgeon can clearly view cutting action on the cornea.
Yet another object of the present invention, in a second embodiment, is to provide a trephine instrument in which the cutting blade is readily removable so that it can serve as a storage container for a removed corneal button. It is contemplated that the blade may be quickly capped on both ends to form a closed, sterile container.
A yet further object of the present invention is to provide a trephine instrument in which the cutting blade is actuated by an ultrasonic source to effect cutting action.
These and additional objects of the present invention reside in the specific construction of the preferred embodiments hereinafter particularly described in the specification and shown in the several drawings.